The present invention is directed to a combine having a separator from which straw is expelled to a discharge assembly, an adjustable straw guide is associated with the discharge assembly. A motor adjusts the straw guide in response to signals from a controller.
When one uses add-on straw choppers attached to combines, the chopped straw should be delivered along a cutting width in as uniform a weight distribution as possible over that width. A conventional straw chopper works with several knives attached to the chopper rotor. This chopper rotor rotates at high rpm and cuts the straw that is fed to it. The rotating knives pass through a stationary knife bar. At the same time, the chopper rotor must generate an air stream capable of blowing out the chopped straw. To achieve an even distribution by the chopper of the chopped straw from the machine channel width to the harvesting platform, feeding of the straw chopper must be done very evenly. Even feeding is also required with combines that operate with two independent discharge means.
In conventional straw walker combines, even feeding of the chopper generally does not present a problem because the loading of the straw walker is very even. In combines with rotating discharge systems, however, even feeding of the straw chopper is not always guaranteed. With these combines, the straw is conveyed by one or two helical threshing and/or separation rotors through a cylindrical and partially eccentric casing.
As a function of various material parameters, especially the material humidity, the number of revolutions about the threshing and/or separation rotor varies in rotor separation systems. As a result, the exit point from the threshing and/or separation rotor, and thus feeding of the straw, also changes. It is thus conceivable, in the case of a combine equipped with two separation rotors, that dry materials will be cast off more toward the middle, and humid materials more toward the outside. For a combine equipped with only one threshing and/or separation rotor, the material is accordingly cast further to the left or to the right.
In DE 43 13 841 A, an axial flow combine is described in which the crop material other than grain (straw) are fed to a straw chopper with a horizontal rotating shaft that is oriented transversely to the direction of movement. A straw guide means is provided between the outlet of the rotor and the inlet of the straw chopper. The straw guide can be rotated about a shaft located in its front area, to allow adaptation to the respective requirements. A motor is provided for remote adjustment of the straw guide device from the cab of the combine.
EP 0 685 151 A proposed a distribution means for a straw chopper of a combine that comprises a number of laterally contiguous guide plates. The guide plates are moved by servomotors that are coupled to sensors which detect the flight path of the exiting chopped material. The sensors work with light, ultrasound, or microwaves. As a result, compensation for crosswind effects is achieved.
The remotely adjustable straw guide of DE 43 13 841 A, can be considered to have the drawback that the combine operator is distracted from more important tasks during adjustment of the straw guide. The operator can inspect the results of adjustment only indirectly and very incompletely based on the ejected straw. This inspection requires observing via the rearview mirror.
The distribution assembly according to EP 0 685 151 A has the drawback that the sensors proposed therein are complicated and expensive. In addition, there is no possibility here to compensate for uneven feeding of the straw chopper at its inlet.
It is an object of the present invention to provide a simple system for transversely distributing chopped straw from the straw chopper.
According to a first aspect of the invention, a sensor determines the transverse distribution of the straw. The sensor is connected to a controller that controls a motor. The motor adjusts a straw guide arranged between the separator and the discharge assembly. The discharge assembly can be a straw chopper or another driven device for discharging straw, for example a rotating straw distribution disc.
In this manner, by means of appropriate control of the motor of the straw guide, one can automatically achieve as even as possible a feeding of the discharge assembly on its inlet side. By using sensor signals, the controller can regulate the motor to correctly position the straw guide and react to disturbances in the flow of straw. If two discharge assemblies are arranged laterally adjacent, approximately identical quantities of straw are fed to them through the straw guide. The type and attachment of the sensor is optional; for example, one can use the sensors known from EP 0 685 151 A.
The sensor for determining the transverse distribution of straw should be located upstream from the outlet of the discharge assembly. Consequently, cost advantageous sensors with a relatively small range can be used. They can be arranged at a relatively protected place inside the housing of the discharge assembly, in this specific case, the straw chopper.
The measurement values of the sensors are fed to the controller, which by means of a motor adjusts the straw guide to influence the transverse distribution of straw. The straw guide can be arranged upstream of the inlet of the discharge assembly; or alternatively, or in addition, it can be arranged downstream from the outlet of the discharge assembly. For this purpose, one can consider using, in particular, straw guide plates that are arranged under the distribution hoods. In this case the motor can move the straw guide means at the side adjacent to the discharge assembly. The straw guide plates are thus moved at the end facing the discharge assembly. As a result, it becomes possible to bring the straw guide plates into positions in which they are fed with chopped straw such that the chopped straw is distributed homogeneously over the cutting width of the combine.
The sensors are used to determine the transverse distribution of the straw. In order to avoid using expensive sensors with a relatively high range, it is possible to distribute several sensors over the width of the flow of straw that are each arranged so as to determine proximate straw flow intensity. Such sensors can operate on the basis of capacitance, or they can sense the sounds caused by impact of the harvest material on surfaces adjacent to the sensor. The last sensor type mentioned is already used to determine grain losses in combines. Another sensor type comprises an element that can be moved by the straw against a force generated, for example, by a spring or by gravity. The position of the element depends on the quantity of straw that flows by, and it is preferably determined by a potentiometer.
The sensor signals can be used by the controller not only to control the motor of the straw guide means, but also to control the combine separator. The separator can thus be operated at a speed at which the straw exits from the separator with as even as possible a width distribution. Alternatively, or additionally, it is also conceivable to adjust the guide plates of a separator casing, which influence the number of rotations of the harvested material within the separator, on the basis of the sensor signals to achieve a uniform width distribution of the straw at the outlet of the separator.